Fatty acid content of New Zealand-grown walnuts (Juglans regia L.)

Walnut (Juglans regia L.) samples were collected during the 1994 and 1995 harvest from ten different cultivars of trees grown in a replicated trial in an experimental orchard at Lincoln University, New Zealand. Two US commercial cultivars (Tehama and Vina), three European commercial cultivars (Esterhazy, 139, G120) and five New Zealand selections (Rex, Dublin's Glory, Meyric, McKinster, Stanley) were evaluated. Total oil was extracted using a cold press and individual fatty acids were analysed by GLC. The total oil content of the nuts ranged from 62.4 to 68.7%. The oleic acid content of the oils ranged from 14.3 to 26.1% of the total fatty acids, while the linoleic acid content ranged from 49.3 to 62.3% and the linolenic contents from 8.0 to 13.8%.     

Antioxidant activities of licorice-derived prenylflavonoids

Glycyrrhiza uralensis (or licorice) is a widely used Oriental herbal medicine from which the phenylflavonoids dehydroglyasperin C (DGC), dehydroglyasperin D (DGD), and isoangustone A (IsoA) are derived. The purpose of the present study was to evaluate the antioxidant properties of DGC, DGD, and IsoA. The three compounds showed strong ferric reducing activities and effectively scavenged DPPH, ABTS⁺, and singlet oxygen radicals. Among the three compounds tested, DGC showed the highest free radical scavenging capacity in human hepatoma HepG2 cells as assessed by oxidant-sensitive fluorescent dyes dichlorofluorescein diacetate and dihydroethidium bromide. In addition, all three compounds effectively suppressed lipid peroxidation in rat tissues as well as H₂O₂-induced ROS production in hepatoma cells. This study demonstrates that among the three phenylflavonoids isolated from licorice, DGC possesses the most potent antioxidant activity, suggesting it has protective effects against chronic diseases caused by reactive oxygen species as well as potential as an antioxidant food additive.     

Antioxidant activities of natural vitamin E formulations

The antioxidant activities of natural d-alpha-tocopherol, mixed tocopherols and tocotrienols, and formulations comprising all forms of vitamin E, providing 400 IU, were determined employing an improved oxygen radical absorbance capacity (ORAC) assay using fluorescein (FL) as the fluorescent probe, randomly methylated beta-cyclodextrin (RMCD), 2,2'-azobis(2-amidino-propane)dihydrochloride (AAPH) as the peroxyl radical generator, and Trolox as the standard in 75 mM phosphate buffer. The antioxidant activities, expressed in micromol Trolox equivalent per gram, of d-alpha-tocopherol (87%), mixed tocopherols (70%), and tocotrienols (30%) were found to be 1,293, 1,948, and 1,229, respectively. Some of the vitamin E formulations showed antioxidant activities superior to d-alpha-tocopherol.     

Antioxidant erythrocyte enzyme activities during oral contraception

Nineteen healthy young women, non-smokers and of normal weight, used a combined oral contraceptive, consisting of 20 μg ethinylestradiol and 150 μg desogestrel, for 9 cycles and were investigated before starting oral contraceptive use, and during the 3rd, 6th and 9th cycle. In all cases, the antioxidant erythrocyte enzyme activities, superoxide-dismutase (SOD), catalase (CAT) and glutathione-peroxidase (GSH-Px), were determined. Pyruvate-kinase (PK) activity was also considered as a predictable index of the age and constancy of the erythrocyte population. A steady, significant increase in GSH-Px and CAT enzyme activities was found. No significant variations were found in SOD and PK enzyme levels. These findings clearly suggest that the use of combined oral contraceptives leads to an increase in antioxidant defenses. The specific physiological and biochemical mechanisms of this response merit further investigation.     

Antioxidant and anti-atherogenic activities of olive oil phenolics

The aim of the current study was to investigate the antioxidant and cellular activity of the olive oil phenolics oleuropein, tyrosol, hydroxytyrosol, and homovanillic alcohol (which is also a major metabolite of hydroxytyrosol). Well-characterized chemical and biochemical assays were used to assess the antioxidant potential of the compounds. Further experiments investigated their influence in cell culture on cytotoxic effects of hydrogen peroxide and oxidized low-density lipoprotein (LDL), nitric oxide production by activated macrophages, and secretion of chemoattractant and cell adhesion molecules by the endothelium. Inhibitory influences on in vitro platelet aggregation were also measured. The antioxidant assays indicated that homovanillic alcohol was a significantly more potent antioxidant than the other phenolics, both in chemical assays and in prolonging the lag phase of LDL oxidation. Cell culture experiments suggested that the olive oil phenolics induce a significant reduction in the secretion of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 (and a trend towards a reduced secretion of monocyte chemoattractant protein-1), and protect against cytotoxic effects of hydrogen peroxide and oxidized LDL. However, no influence on nitric oxide production or platelet aggregation was evident. The data show that olive oil phenolics have biochemical and cellular actions, which, if also apparent in vivo, could exert cardioprotective effects.     

Antioxidant activities of selected Chinese medicinal and edible plants

The antioxidant activities and contents of total phenols of 33 plants were evaluated using the ferric-reducing antioxidant power assay and Folin-Ciocalteu method. Significant linear correlation between the antioxidant activity and total phenolic content was found. The results show that a number of Chinese medicinal and edible plants, especially Flos Caryophylli, are important raw materials of the antioxidant functional foods or ingredients.     

Antioxidant and antiviral activities of silybin fatty acid conjugates

Two selective acylation methods for silybin esterification with long-chain fatty acids were developed, yielding a series of silybin 7-O- and 23-O-acyl-derivatives of varying acyl chain lengths. These compounds were tested for their antioxidant (inhibition of lipid peroxidation and DPPH-scavenging) and anti-influenza virus activities. The acyl chain length is an important prerequisite for both biological activities, as they improved with increasing length of the acyl moiety.     

Antioxidant and antimutagenic activities of Cinnamomum zeylanicum fruit extracts

Recently, a number of studies on the health benefits associated with natural compounds have been demonstrated. Phenolics in fruits, vegetables, herbs and spices possess potent antioxidant, anti-inflammatory, antimutagenic and anticarcinogenic activities. In the present study, the dried fruits of cinnamon were extracted with ethyl acetate, acetone, methanol and water using a Soxhlet extractor. The total phenolics content of the extracts as determined by Folin–Ciocalteu method were found to be the highest in water extract (44.5%) and the lowest in ethyl acetate (14.4%). The antioxidant activity (AA) of the extracts was evaluated through in vitro model systems such as β-carotene-linoleate, and 1,1-diphenyl-2-picryl hydrazyl (DPPH); the antimutagenicity of these extracts was also assayed against the mutagenicity of sodium azide by Ames test using tester strain of Salmonella typhimurium (TA100) at different concentrations. In both the model systems, the AA of the extracts was found in the order of water>methanol>acetone>ethyl acetate. All the extracts decreased sodium azide mutagenicity in S. typhimurium strain (TA100). At 5000 μg/plate all the extracts showed strong antimutagenicity. The antimutagenicity of water extract was followed by acetone, methanol and ethyl acetate. The results of the present study indicate that under-utilized and unconventional part of cinnamon is a good source of antioxidant and antimutagenic phenolics.     

Antioxidant activities of various fruits and vegetables produced in Taiwan

Fruits and vegetables have been known to contain a variety of antioxidant components. It has been suggested that antioxidants may protect biomolecules from oxidative damage and therefore be associated with reduced risks of cardiovascular disease and certain cancer. The antioxidant abilities of various parts of eight common fruits and vegetables produced in Taiwan were investigated, including tomato, guava, squash, tangerine, wax gourd, pineapple, chayote, and eggplant. Squash, wax gourd, tomato, and guava seeds showed the highest antioxidant activities in thiobarbituric acid assay. Wax guard and squash seeds showed the highest antioxidant activities in iodometric assay. At the level of 1 g fresh sample, low-density lipoprotein peroxidation was inhibited by at least 90% by tomato meat, guava meat, squash seed, wax gourd meat, core, and seed, and eggplant skin. The total phenolic content was significantly correlated with antioxidant activities measured by thiobarbituric acid (r=0.715, P<0.01) and iodometric (r=0.749, P<0.01) assays. The results of this study could be used for development of merchandise with potential health benefits from agricultural products.     

Antioxidant and free radical scavenging activities of some leafy vegetables

Some leafy vegetables were studied for their nutritional composition, antioxidant and free radical scavenging activities. The aerial parts of Coriandrum sativum, Spinacia oleracea, Trigonella corniculata and Trigonella foenum-graecum showed lower inhibitory concentration values (4.1-7.9 mg/ml), efficiency concentration values (178-321 mg/mg DPPH) and higher values of anti-radical power (0.31-0.51) as compared with their seeds. Thermal treatment reduced the total phenolic contents, antioxidant and free radical scavenging activities. The leaves of C. sativum were found with good amounts of caffeic acid, ferulic acid, gallic acid and chlorogenic acid.     

Antioxidant activities of various fruits and vegetables produced in Taiwan

Fruits and vegetables have been known to contain a variety of antioxidant components. It has been suggested that antioxidants may protect biomolecules from oxidative damage and therefore be associated with reduced risks of cardiovascular disease and certain cancer. The antioxidant abilities of various parts of eight common fruits and vegetables produced in Taiwan were investigated, including tomato, guava, squash, tangerine, wax gourd, pineapple, chayote, and eggplant. Squash, wax gourd, tomato, and guava seeds showed the highest antioxidant activities in thiobarbituric acid assay. Wax guard and squash seeds showed the highest antioxidant activities in iodometric assay. At the level of 1 g fresh sample, low-density lipoprotein peroxidation was inhibited by at least 90% by tomato meat, guava meat, squash seed, wax gourd meat, core, and seed, and eggplant skin. The total phenolic content was significantly correlated with antioxidant activities measured by thiobarbituric acid (r=0.715, P<0.01) and iodometric (r=0.749, P<0.01) assays. The results of this study could be used for development of merchandise with potential health benefits from agricultural products.     

Antioxidant and antidiabetic activities of extracts from Cirsium japonicum roots

This study investigated the antioxidant activity of methanol (MeOH) and water extracts from roots of Cirsium japonicum in vitro. MeOH extract showed a stronger free radical scavenging activity than water extract. However, both of extracts showed a concentration dependent hydroxyl radical scavenging activity, reducing power and metal chelating ability. MeOH extract had greater phenolic and flavonoid contents than water extract. The antidiabetic activity of these two extracts was evaluated by the α-glucosidase inhibition assay. The water extract showed a considerable α-glucosidase inhibitory activity. To our knowledge, this may be the first time to report the antioxidant and antidiabetic activities in Cirsium japonicum roots.     

Antioxidant activities of some Greek wines and wine phenolic extracts

Antioxidant activities and phenolic composition of eight Greek wines were determined. Red wines scavenged 1,1′-diphenyl-2-picryl-hydrazyl radical (DPPH) to a much greater degree than whites, in proportion to their phenolic contents. Red wines inhibited β-carotene bleaching, while white wines were almost inactive. Red wines were more active than quercetin in DPPH and less active in β-carotene assay. Xinomavro-red must exhibited significant activities in both assays. Roditis-white must scavenged DPPH, and exhibited some activity in β-carotene assay. Young Xinomavro and Roditis wines and their extracts were more active in scavenging DPPH than the respective aged wine and extracts. However, young Xinomavro wine and its extracts were less active than those of aged wine in β-carotene assay. Roditis wine extracts exhibited only limited activity in β-carotene assay. Xinomavro young and aged wine extracts rich in anthocyanins and flavanols were more active than the others in both assays used.     

Antioxidant and free radical scavenging activities of some leafy vegetables

Some leafy vegetables were studied for their nutritional composition, antioxidant and free radical scavenging activities. The aerial parts of Coriandrum sativum, Spinacia oleracea, Trigonella corniculata and Trigonella foenum-graecum showed lower inhibitory concentration values (4.1–7.9 mg/ml), efficiency concentration values (178–321 mg/mg DPPH) and higher values of anti-radical power (0.31–0.51) as compared with their seeds. Thermal treatment reduced the total phenolic contents, antioxidant and free radical scavenging activities. The leaves of C. sativum were found with good amounts of caffeic acid, ferulic acid, gallic acid and chlorogenic acid.     

Antioxidant levels and activities of selected seeds of malaysian tropical fruits

The aims of this study are to determine and compare the antioxidant levels and activities (i.e. primary and secondary) between selected seeds of Malaysian tropical fruits - guava (Psidium guajava), mango (Mangifera indica L.) and papaya (Carica papaya L.). Seeds are among byproducts from the processing of fruitsbased products. Instead of discarding seeds as waste, seeds with high potential as antioxidants could be utilised for commercial purposes. Accordingly, the selected seeds of Malaysian tropical fruits were tested in this study for total phenolic content (TPC), free radical scavenging activity by 1, 1- diphenyl-2-picrylhydrazyl (DPPH) assay and metal ion chelating effect by ferrous ion chelating (FIC) assay. Extraction of antioxidant compounds from sample was done with 70% ethanol. TPCs of the seeds were expressed as gallic acid equivalents (GAE) in mg per 100 g fresh seed weight. TPC assay showed that mango seeds had the highest TPC (i.e. 32 ± 0.001 mg GAE) followed by guava seeds (i.e. 20 ± 0.001 mg GAE) and papaya seeds (8 ± 0.003 mg GAE). For DPPH assay, IC50 data showed that mango seed extract scavenged 50% DPPH radicals at the lowest concentration (0.11 ± 0.01 mg/mL) followed by the positive control BHA (0.13 ± 0.01 mg/mL), guava seed extract (0.26 ± 0.01 mg/mL) and papaya seed extract (0.34 ± 0.01 mg/mL). Interestingly, all seed extracts showed higher free radical scavenging activities than BHA after sample concentration of 0.60 mg/mL. However, FIC assay indicated that metal ion chelating effects of all seed extracts were weaker than BHA suggesting that the fruit seeds are not sources of good metal ion chelators. Overall, present results suggest that TPC of the seeds show strong negative correlation with their primary antioxidant activity (r= -0.985, R2= 0.970), and not all compounds in extracts which could scavenge DPPH radicals are good metal ion chelators. Mango seeds relatively showed the highest antioxidant level and primary antioxidant activity followed by guava seeds and papaya seeds.     

Antioxidant and prooxidant activities of B group vitamins in lipid peroxidation

The antioxidant and prooxidant activities of six B group vitamins against hydroperoxide generation in linoleic acid peroxidation were analyzed by the aluminum chrolide method. The B group vitamins were divided into three types by their antioxidant and prooxidant properties. The first type, including B1, B2 vitamin, nicotinic acid and folic acid, showed prooxidant activities in the early phase (1 week) of the linoleic acid peroxidation at concentrations of 2.5 microM-2.5 mM, but caused relatively strong antioxidant activities in the later phase reaction (3 weeks) at the same concentrations. The second type, such as B12 vitamin, did not cause significant effects in the early phases (1-2 weeks) of linoleic acid peroxidation, but exhibited significant antioxidant activities in the later phase reactions (3 weeks). The third type, such as B6 vitamin, exhibited significant antioxidant activity in the early phase reaction and caused strong antioxidant effects in the later phase reaction (3 weeks). Generally, the antioxidant activities of B group vitamins in the later phases of lipid peroxidation was much stronger than those in the earlier phases. These experimental results suggest a possibility that B group vitamins have both antioxidant and prooxidant effects on lipid peroxidation under different experimental conditions.     

Antioxidant activities of various extracts of lotus (Nelumbo nuficera Gaertn) rhizome

Lotus rhizome powder was extracted with solvents of different polarities. Antioxidant activities of the extracts were evaluated by a 2, 2'-diphenylpicrylhydrazyl (DPPH) assay and a beta-carotene bleaching assay, and compared with that of butylated hydroxyanisole (BHA) and ascorbic acid. Methanol showed the highest extract yield among all of solvents. Although acetone extract had the highest total phenolics content, methanol extract had the highest total phenolics recovery from lotus powder (20.1 mg catechin equivalents/100g lotus powder). Extract of either methanol or acetone demonstrated the highest DPPH scavenging activity at both 66.7 mg/L and 133.3 mg/L. All extracts exhibited higher antioxidant activity coefficient (AAC) than that of ascorbic acid, furthermore, dichloromethane and petroleum extracts had comparable AAC with BHA by the beta-carotene bleaching assay. The properties of the extracting solvents significantly affected the yield, total phenolics content and antioxidant activity of lotus rhizome extracts.     

Antioxidant activities of the water-soluble fraction in tempeh-like fermented soybean (GABA-tempeh)

Tempeh is a traditional fermented soyfood native to Central Java, Indonesia; tempeh is prepared by salt-free aerobic fermentation using Rhizopus. Similar to miso, tempeh is also reported to be antioxygenic. In this study, we used a tempeh-like fermented soybean. First, soybean was incubated aerobically and then successively incubated anaerobically. Because the gamma-amino butyric acid (GABA) content was increased remarkably, we named this tempeh GABA-tempeh. The contents of other free amino acids and peptides were significantly higher in GABA-tempeh than in conventional tempeh. In this study, we compared the antioxidant activity of the water-soluble fraction in GABA-tempeh with that of soybean and conventional tempeh. The order of the antioxidant activity was shown as follows: GABA-tempeh > conventional tempeh > soybean. The components responsible for the antioxidant activity of GABA-tempeh were isoflavone aglycones, free amino acids, and peptides, which increased during aerobic and anaerobic fermentations.